System for introducing a pump

ABSTRACT

The invention resides in the field of introducing fluid pumps into a lumen and relates to a system for introducing a pump into a lumen which comprises a first sheath and a pump to be introduced into the first sheath, or a system which has a pump with a distal pump unit and a shaft catheter which emerges proximally to the pump unit. According to the invention one or two sheaths are used, the distal pump unit being pulled firstly into the distal end of one sheath, in order to avoid damage to a shaft catheter. Subsequently, the sheath receiving the pump unit is transferred into a further sheath or a receiving lumen.

The invention resides in the field of introducing fluid pumps into alumen and relates to a system for introducing a pump into a lumen, whichcomprises a first sheath and a pump to be introduced into the firstsheath, or a system which has a pump with a distal pump unit and a shaftcatheter which emerges proximally to the pump unit.

The application can hence be provided, on the one hand, in the minimallyinvasive medical field, for example as a blood pump for heartassistance, and, on the other hand, also use in agitators or as a driveelement is conceivable.

The invention can display special advantages by the possibleminiaturisation in the medical field. Techniques for introducing fluidpumps, in particular into natural body lumina, are known in detail inprior art. Thus reference is made inter alia to the Seldinger techniquefor introducing an introducer sheath into a vascular system. Thetechnique and possible variants are intended to be explained in moredetail with reference to FIG. 1.

A schematic human vascular system 1 is shown in FIG. 1. In the groinregion there is one of the femoral arteries 2 which is connected to theaortic arch via a main artery and subsequently opens into the ventricle4. With the help for example of the Seldinger technique, firstly anintroducer sheath 10 is introduced into the femoral artery 2. Firstly,the femoral artery or any blood vessel is hereby punctured with a steelcannula with a cutting tip. A guide wire 12 is pushed through the steelcannula introduced into the puncture and is introduced retrogressivelyvia the aortic arch 3 into the left ventricle 4. After removing thepuncturing cannula, the first sheath 10 which is configured asintroducer sheath and comprises a tubular portion 11 is threaded ontothe guide wire and introduced into the vascular system through thepunctured point, the sheath being introduced into the lumen of thevascular system merely by a small distance. Subsequently, a fluid pumpis introduced into the vascular system through the introducer sheath 10.

Such a method is known for example from WO 02/43791 A1. After theintroducer sheath, as represented in FIG. 1, has been introduced intothe vascular system, a heart pump is pushed forwards along the guidewire 12 into the left ventricle 4. The pump, in particular a distal pumpunit, is thereby pushed outside the sheath through the vascular systemtowards the ventricle.

Modern fluid pumps often rotate at high speeds in order to be able toconvey a corresponding quantity of fluid per minute. Such a blood pumpcan be deduced for example from the above-mentioned WO 02/43791 A1 orfrom EP 2 047 872 A1. The latter shows a pump which has a distal pumpunit, a shaft catheter abutting against the proximal end of the distalpump unit, the shaft catheter in turn being able to be connected to adrive unit for driving the fluid pump.

One disadvantage in the previously known systems for introducing a pumpinto a lumen is the great danger of damaging the shaft extending in theshaft catheter, which has a negative effect on the lifespan or theuseful life of the pump unit.

Starting from the known state of the art, it is the object of thepresent invention to reduce the danger of damaging the shaft catheter ofa pump.

The object is achieved by a system according to the features of claim 1or with the help of a system according to the features of claim 12.Furthermore, methods for introducing and removing pumps are included bythe invention.

Further embodiments are cited in the subordinate and coordinated claims.

A first aspect of the invention is offered by a system for introducing a(preferably expandable) pump (for particular preference self-expandablerotary pump) into a lumen, the system comprising a first sheath and apump to be introduced into the first sheath and the first sheath havinga first sheath lumen which extends from a distal end to a proximal endfor introducing the pump.

A self-expanding pump can be decompressed on the basis of being takenout of the sheath since the sheath no longer restricts the radius of thepump. Alternatively, the self-expanding pump can have a material whichchanges its state on the basis of the flow conditions, the temperatureprevailing in the vascular system or the pressure and thus effectsdecompression of the pump unit taken out of the sheath.

With regard to the details of the pump (according to the aspects of theinvention presented in this application), reference is made to theentire disclosures of U.S. Provisional Applications No. 61/120,095,filed on Dec. 5, 2008, No. 61/149,753, filed on Feb. 4, 2009 No.61/151,964, filed on Feb. 12, 2009, No. 61/161,125, filed on Mar. 18,2009 No. 61/162,710, filed on Mar. 24, 2009, No. 61/173,666, filed onApr. 29, 2009, No. 61/175,519, filed on May 5, 2009, No. 61/220,292,filed on Jun. 25, 2009, No. 61/231,787, filed on Aug. 6, 2009, No.61/244,592, filed on Sep. 22, 2009, No. 61/244,600, filed on Sep. 22,2009, No. 61/244,608, filed on Sep. 22, 2009, No. 61/244,614, filed onSep. 22, 2009, No. 61/254,315, filed on Oct. 23, 2009, No. 61/254,339,filed on Oct. 23, 2009, No. 61/289,569, filed on Dec. 23, 2009, No.61/289,645, filed on Dec. 23, 2009, No. 61/289,656, filed on Dec. 23,2009, No. 61/293,270, filed on Jan. 8, 2010, No. 61/297,858, filed onJan. 25, 2010, No. 61/298,581, filed on Jan. 27, 2010, No. 61/310,750,filed on Mar. 5, 2010, No. 61/345,253, filed on May 17, 2010, No.61/358,496, filed on Jun. 25, 2010, No. 61/364,559, filed on Jul. 15,2010, No. 61/364,578, filed on Jul. 15, 2010, No. 61/364,595, filed onJul. 15, 2010, and No. 61/451,222, filed on Mar. 10, 2011, which arehereby incorporated by reference in this application in their entirety.

There is understood by the term sheath in the present application,essentially a lumen which is surrounded by a casing and has a distal anda proximal opening. Preferably, the sheath is configured such that thiscan receive a shaft catheter, for example a shaft catheter with adiameter of 5-15 Fr, preferably 7-11 Fr. In addition, a sheath ispreferably flexible so that this can be guided through a natural bodylumen. This applies both to the first and the second sheath.

According to the invention, the system comprises furthermore a secondsheath with a second sheath lumen which extends from a distal end to aproximal end and in which the pump is retained in a guidable manner. Thesecond sheath is thereby configured such that it can be coupled to thefirst sheath for transferring the pump from the second into the firstsheath.

The second sheath offers additional protection for the shaft catheterduring introduction of the pump. In this way, an improved introductionof the pump into the first sheath or into the first sheath lumen is madepossible.

In the sense of the present invention, “sheath” implies an objectthrough which something different can be guided. Such a sheath can, butneed not necessarily, have a haemostatic valve.

Since threading the pump into a sheath is associated generally withgreat care and hence associated with considerable time expenditure, thesecond sheath makes threading the pump unit into the same possiblebefore the actual transfer of the pump into the lumen which receives thepump. In other words, the pump can be inspected firstly well before anoperation and subsequently threaded into the second sheath, preferablypulled in, threading in being able to be undertaken without pressure oftime.

At the time of the operation, the second sheath in which the pump isfirstly retained must now be coupled merely to the first sheath, and thepump can be transferred directly from the second into the first sheath.This reduces the probability of damaging the pump or the shaft andenables thus an improved running performance or running time of the pumpitself. Also, the time expenditure for introducing the pump which isrequired during for example an operation is reduced.

A second aspect of the invention relates to a system which can be usedin the above-mentioned system, having a pump which comprises a distalpump unit and a shaft catheter which emerges proximally to the pumpunit. In addition to the pump, the system has furthermore a sheath witha sheath lumen which is disposed proximally to the distal pump unit, thesheath lumen surrounding a portion of the shaft catheter. The featuretermed merely sheath is designated in the system of the first aspect ofthe invention generally as second sheath. Such features relate to thesystem according to the second aspect.

The sheath is configured such that the sheath can be displaced along theshaft catheter in the direction of the distal pump unit and the distalpump unit can be introduced into the sheath lumen. This presupposes thatthe inner diameter of the sheath lumen is greater than the outerdiameter of the shaft catheter.

In the system consisting of the pump and the sheath, it is advantageousin particular that pulling can take place on the shaft catheter forpulling in the distal pump unit into the distal end of the sheath.Since, when pulling the shaft, the danger of distortions or damage orbending of the shaft relative to pressing in or pushing in the deviceinto a sheath is significantly reduced, the running time or lifespan ofthe pump unit is improved relative to the conventional methods forintroducing the pump and the systems used there.

After the pump has been pulled into the sheath and the distal end of thedistal pump unit is situated partially or completely proximally to thedistal end of the sheath, the system of the second aspect can becoupled, according to the first aspect of the invention, to a firstsheath so that more simple introduction of the pump unit into the lumenwhich ultimately receives the pump, such as e.g. a blood vessel, isachieved.

According to a third aspect of the invention, the systems of the firstor second aspect of the invention can be further improved. The thirdaspect comprises a device for retaining a portion of the sheath of thesecond aspect or of the second sheath of the first aspect. The devicefor retaining the portion of the sheath is thereby configured such thatit can retain the sheath frictionally, on the one hand, and on the otherhand, prevent deformation, in particular bending, of the sheath in theretained region. Due to the device for retaining a portion of thesheath, a possibly present intrinsic reinforcement of the sheath, forexample in the form of a wire mesh, is not required since the retainingdevice effects reinforcement of a portion of the sheath. This leads tothe fact the bending of the shaft when pulling the pump into the lumenof the sheath is not possible and when transferring the pump from thesheath retained by the device into the first sheath is possible but madedifficult.

The three aspects described in the preceding paragraphs each form per sean independent patentable part of the invention. Although the thirdaspect, i.e. the device for retaining a portion of a sheath, has beendescribed merely as an improvement to the system of the second aspect,an independent significance is also attributed to it. The commoninventive idea is to introduce the pump into a second sheath beforeintroduction into the lumen which is to receive the pump withoutpressure of time.

All three aspects are suitable per se for preventing bending of theshaft of a pump.

Further embodiments of the different aspects are subsequently dealtwith.

In one embodiment of the first aspect of the invention, the first sheathlumen has, in regions, a smaller inner cross-sectional area, preferablya smaller inner diameter, than the second sheath lumen. This has theadvantage that threading the pump into the second sheath can beundertaken in a simplified manner. A ratio between 1:1 and 1:1.2 ispossible as a suitable size ratio of the inner cross-sectional area ofthe first sheath lumen to that of the second sheath lumen.

In a further embodiment of the system of the first aspect, the firstsheath comprises a first sheath valve at the proximal end thereof. Withthe help of the sheath valve, the introducer sheath can firstly beintroduced into the lumen receiving the pump and leakage of a fluid outof the pump can be prevented.

The sheath valve is thereby preferably configured such that it has awider inner cross-section than the sheath lumen. Also a conicallytapering shape of the sheath valve is included by the embodiment. Thesheath valve thereby tapers from its proximal end to the distal end,i.e. towards that end at which it is connected to the sheath lumen.Alternatively or in combination, the first sheath lumen can beconfigured such that this widens in the region of connection between thesheath lumen and the sheath valve.

The sheath is configured according to the invention such that the distalend of the second sheath can be introduced at least partially into thefirst sheath valve and the coupling between the first and second sheathis produced in this way.

In one embodiment of the first and second aspect of the invention, thesecond sheath is a tear-off sheath or a “peel-away” sheath which can betorn off over its entire length. Sheaths of this type have for example amolecular structure which facilitates tearing off from the proximal endtowards the distal end. The tear-off sheath can however also beconfigured to be able to be torn off for example by a material taperingin the manner of a predetermined breaking point or by a longitudinallyinserted tear-off wire or thread. As a result, the second sheath, afterthe pump has been transferred from the second sheath into the firstsheath, can be torn off and withdrawn from the pump, in particular fromthe shaft catheter extending therein. The second sheath represents, inthis variant, a feature of the invention which is connected to the pumpmerely before introduction into the lumen which receives the pump.

In a further embodiment of the first and second aspect of the invention,the first and the second sheath comprise a plastic material which can beprovided, in a further embodiment, with a strengthening or reinforcingstructure. Plastic material represents a particularly suitable materialchoice in the medical field.

In an embodiment of the third aspect, the device for retaining a portionof the second sheath comprises a cavity in which the portion of thesecond sheath can be retained frictionally. This can be achieved forexample via a roughened surface of the cavity. Another possibilityresides in configuring the inner cross-sectional area of the cavityminimally less than the outer cross-sectional area of the second sheath.As a result of the fact that the device has a cavity, the surfacessurrounding the cavity can serve as retaining surface for an operator ofthe system. Also as a result, damage to the shaft is avoided. There ispossible as material, for example, metal or even a plastic material inorder to avoid the transmission of pathogens from the device to thesheath. In the case of use in a human or animal body, preferablybiocompatible materials should be used.

In a further embodiment of the third aspect, the device is configuredsuch that the second sheath can be received, over preferably at leasthalf of its length, by the device for retaining the second sheath.

In a further embodiment, the device is configured such that the retainedportion of the second sheath comprises a curvature of less than 10°,preferably less than 5′, particularly preferred less than 1°. Due to acurvature of the second sheath, the danger of the shaft bendingincreases. This can be avoided by a corresponding configuration of, thedevice for retaining a portion of the second sheath.

By means of a curvature of the receiving region of the second sheath onthe device, the second sheath is fixed axially without restricting thelumen L2 of the second sheath. For this purpose, the 2^(nd) sheathshould have an appropriate bending resistance. Alternatively, the 2^(nd)sheath can also have a curvature and the device can be straight (or bothcurved).

For this purpose, a system according to the invention provides that thedeviations from the straightness of the second sheath in the clampedregion and of the device for retaining a portion of the second sheathare together greater than the difference of the inner diameter of thedevice for retaining a portion of the second sheath and of the outerdiameter of the second sheath, see FIGS. 15a and 15 b.

The system according to the first aspect can be used in conjunction witha system according to the second aspect such that firstly the firstsheath is introduced into the lumen which subsequently receives the pumpsuch that the proximal end of the first sheath is accessible outside thereceiving lumen. Before or thereafter, the distal end of the pump can bemoved into the sheath lumen of the second sheath, preferably can bepulled into the second sheath with the help of a system according to thesecond aspect.

For this purpose, the second sheath can be reinforced at least axiallyin the distal region thereof. Hence bending of the pump or of the secondsheath when pulling the pump into the sheath can be prevented.

Subsequently, the distal end of the second sheath is coupled to theproximal end of the first sheath and the pump is transferred from thesecond sheath into the first sheath.

In one embodiment, the distal end of the pump is subsequently guidedthrough the distal end of the first sheath lumen into the lumen whichreceives the pump.

In one method for designing the pump, the distal pump unit which isplaced distally to the distal end of the sheath remaining in thevascular system is pulled into the sheath and subsequently removed fromthe receiving lumen through the sheath. Alternatively, the pump can beremoved together with the receiving lumen.

In one embodiment of the method for designing the pump, the distal endof the sheath is situated during the operating state of the pump unitless than 20 cm, preferably less than 10 cm, away from the operatinglocation of the pump unit. As a result, transport of the pump unit tothe operating location and away from this is simplified. Furthermore,the vascular system is hereby protected from lesions by the pump (duringtransport of the same).

The present patent application relates in addition to a catheter pump,which can be introduced into human or animal vessels in a compressedstate and can be operated in an expanded state in a lumen of the humanor animal body in order to convey a fluid, the catheter pump having arotor for conveying fluid, a housing which surrounds the rotor and is atleast partially fluid-permeable and also an introducer sheath close tothe rotor, wherein, during transfer from the expanded state into thecompressed state, the housing can be introduced into the introducersheath for narrowing of the diameter at least in regions, and thisnarrowing of the diameter of the housing is dimensioned such that alsothe diameter (i.e. the largest outer diameter) of the rotor is reducedby the narrowing of the diameter of the housing from the expanded stateto the compressed state.

The invention described in the preceding paragraph is per se forcatheter pumps an independent invention so that the applicant reservesthe right to direct a separate partial application thereto subsequently.

Advantageous developments of this catheter pump (see previous paragraph)can be detected from the originally filed FIGS. 1 to 15 b, in particularfrom FIG. 4, 5 or 6.

All the embodiments or originally filed patent claims mentioned here,provided that this is not technically contradictory, should be valid aspossible developments.

The basic principle mentioned in the originally filed patent claim 23 isbased on the fact (this applying of course to all aspects of theapplication) that the introducer sheath itself does not compress therotor but that this takes place directly by means of a housingsurrounding the rotor. In other words, a fixed spatial arrangementexists between the rotor and the housing surrounding the rotor, i.e. therotor is not moved independently of the surrounding housing. The fixedspatial arrangement may be understood as the proximal or distal end ofthe rotor being fixed with respect to at least one location of thesurrounding housing. This housing can (as shown in this application)have a grid structure which is closed in regions. As a result, suctionof fluid into the housing is possible and conveyance to the proximal endof the catheter is possible. The mentioned rotor can have various forms,for example it can have different rotor blades, these individual rotorblades being also able to have lamellae. The rotor can also have anouter plastic material surface and be configured for example as aplastic material cast or injection moulded part. It is important thatthe rotor can also have a compressed state for introduction into thevessel (or the housing/the sheath) and also an expanded state in which aconveying operation is possible and in which the rotor is protected bythe surrounding housing. A gap between the radial rotor outer edges andthe housing can hereby exist. Even during operation the housing can bedisposed still in regions in the introducer sheath close to the rotor aslong as free rotation of the rotor is not impeded as a result.

Furthermore, the shaft can be coupled to the motor by means of amagnetic coupling.

The above-mentioned inventions are therefore suitable in particular forself-decompressible pumps.

The invention is intended to be explained subsequently in more detailwith reference to a few embodiments. There are shown:

FIG. 1 a schematic overview of a vascular system with an introducedfirst sheath;

FIG. 2 a detailed view of a cut-out of FIG. 1;

FIG. 3 an embodiment of a system according to the first aspect of theinvention;

FIG. 4 an embodiment of a pump;

FIG. 5 an embodiment of a system according to the second aspect of theinvention;

FIGS. 6, 7 pulling a pump into a second sheath;

FIG. 8, 9 transfer of a pump from a second into a first sheath;

FIG. 10 an embodiment of the system according to the second aspect witha device according to the third aspect of the invention;

FIG. 11 a cross-section of the representation of FIG. 10;

FIG. 12 an embodiment according to the first and third aspect of theinvention;

FIGS. 13a and 13b an embodiment of a distal end of a sheath according tothe second aspect of the invention;

FIG. 14 an embodiment of a long sheath and the arrangement thereofduring the operating state of the pump unit;

FIGS. 15a and 15b sketches for clarification of curves.

As already mentioned initially, FIG. 1 shows a schematic representationof a human vascular system in which a first sheath 10 configured as anintroducer sheath has been introduced into the femoral artery withapplication of the Seldinger technique.

In FIG. 1, a guide wire 12 which extends into to the left ventricle isshown furthermore. The tubular portion 11 of the first sheath 10 isintroduced into the artery such that the proximal end of the firstsheath 10 is situated outside the femoral artery and hence can be usedto introduce for example a pump. On the one hand, it is possible tothread the pump onto the guide wire 12 in order to guide the pump intothe left heart ventricle by means of the guide wire.

It is a method according to the invention to guide the tubular portion11 of the first sheath 10, guided by the guide wire, into the leftventricle and subsequently to remove the guide wire 12 from the firstsheath. A possible pump unit is subsequently guided through the firstsheath lumen into the vicinity of or into the left ventricle 4.

The invention is presently represented merely with reference tointroduction of a pump into the left ventricle for assisting a heartfunction. However, it can be detected easily by the person skilled inthe art that the pump can be disposed also at other positions in thenatural body vascular system. Furthermore, it is evident to the personskilled in the art that the invention is not restricted exclusively tothe natural body vascular system but is suitable for introduction of apump into any lumina. This includes for example lumina which are definedby tubes, into which a pump unit is intended to be introduced forconveying a flow.

In FIG. 2, the region of FIG. 1 in which the first sheath 10 is guidedthrough the natural body tissue from outside into the lumen L_(G) of thefemoral artery 2 is represented. The first sheath thereby comprises atubular portion 11 which is connected proximally to a valve 13. Thetubular portion 11 defines a lumen L₁ which has an inner diameter d₁₁.The latter widens in the manner of a trumpet towards the proximal end ofthe tubular portion 11. The trumpet-like widening 14 leads to thediameter of the valve 13 being greater than the inner diameter d₁₁.

The valve 13 concerns a haemostatic valve which is known in prior artand comprises a housing 15 and a gasket 16. The haemostatic valveprevents fluid situated in the lumen L_(G) from emerging outwardsthrough the lumen L₁.

In the illustration of FIG. 3, the first sheath 10 of FIG. 2 is coupledto a second sheath 20. Merely a tubular portion 21 of the second sheath20 which defines a lumen L₂ with an inner diameter d₂₁ is shown. Thedistal end of the second sheath 20 which is coupled to the valve 13thereby has such an outer diameter that it can be introduced into thevalve 13. The inner diameter d₂₁ is however greater than the innerdiameter d₁₁.

At this point, reference may be made to the fact that the position ofthe valve is not restricted to the proximal end of the first sheath butcan also be disposed at other positions inside the first sheath, such asfor example the distal end of the first sheath or in the centre. It issufficient for introducing the distal end of the second sheath into theproximal end of the first sheath if the proximal end of the first sheathhas an inner diameter which is greater than the outer diameter of thedistal end of the second sheath. The diameter of the lumen of the firstand second sheath (apart from the proximal end of the first sheath andthe distal end of the second sheath) can be uniform or different or thelumen of the respective sheath can be tapered.

The first and second sheath and also the distal pump unit are configuredsuch that the distal pump unit can come to be situated in the first andsecond sheath, whilst the proximal end of the second sheath is situatedin the distal end of the first sheath or is coupled thereto.

A pump situated in the lumen L₂, not illustrated, can now be transferredfrom the second sheath lumen L₂ into the first sheath lumen L₁ bypressing. Subsequently, the pump is transported through the first sheathlumen L₁ to the position in the vascular system at which the pump isintended to develop its action. The pump can either be guided on a guidewire or be introduced without a guide wire through the first sheathlumen.

A possible embodiment of a pump 30 is explained in more detail withreference to FIG. 4. The pump 30 comprises a distal pump unit 31 and ashaft catheter 32 which abuts against the proximal end of the distalpump unit 31. At its proximal end, not illustrated, the shaft catheter32 has a coupling for coupling the shaft catheter 32 to a drive device.The drive device sets a flexible shaft which extends in the shaftcatheter 32 in rotation, which shaft in turn actuates the distal pumpunit 31.

The distal pump unit comprises a pump housing 33 which is produced fromintersecting nitinol struts. The nitinol housing is provided in partswith a coating 34 which extends distally and proximally to a rotor 35disposed in the housing 33. The rotor is connected to the shaft 36 whichextends through the shaft catheter 32 and is thus set in rotation. Thehousing and the rotor are compressible, i.e. the pump is aself-decompressible pump. The unfolding of the pump is performed afterthe distal pump unit is pushed out of the distal end of one sheath. Forcompression of the pump, the distal pump unit is pulled into the distalend of a sheath lumen. The sheath lumen thereby has an inner diameterwhich is at least greater than the outer diameter of the shaft catheter.

The distal pump unit is constructed such that the housing surroundingthe pump is essentially fixed in the axial direction relative to therotor, i.e. the rotor is not removed from the housing during theimplantation but remains in the same.

Optionally, the pump has a discharge hose 37 which defines a flowchannel for the pumped fluid, situated proximally to the rotor 35. Atthe proximal end of the discharge hose 37, outlet openings which are notillustrated in more detail are situated.

Of course, the pump can also be switched from a pumping operation to asuction operation so that the pump no longer conducts fluid from thedistal end to the proximal end, but vice versa.

A detailed description of a further suitable pump can be deduced forexample from the publication EP 2 047 872 A1.

The function of the system according to the second aspect is nowintended to be explained with reference to FIGS. 5 to 9.

In FIG. 5, a pump 30′ which corresponds essentially to the pump 30according to FIG. 4 is represented. For simplification, details of thepump are not shown. Merely the bulbous housing and also the “pigtail”situated distally to the bulbous housing are represented, which housingprevents suction of the heart pump against the heart wall. The shaftcatheter 32′ extends proximally to the distal pump unit 31′. Surroundinga region 38′ of the shaft catheter 32′, a second sheath 20′ is disposed,which comprises a lumen L₂, the inner diameter d₂₁ of which is less thanthe diameter of the distal pump unit 31′ in the decompressed or unfoldedstate.

The pump 30′ illustrated in FIG. 5 is a compressible pump, i.e. thedistal pump unit 31′ which comprises inter alia the pump housing and therotor situated therein is configured such that it can be compressed,i.e. reduced in its diameter. After a quality tester or for example adoctor has been able to convince himself of the correct function of thepump 30′, e.g. by observing the rotational movement of the rotor unitsituated in the distal pump unit 31′ during a test run, the distal pumpunit 31′ is pulled into the lumen L₂ of the second sheath 20′ by pullingthe shaft catheter 32′ in the proximal direction. By pulling the pumpinto the second sheath 20′, bending or damage to the shaft catheter orthe shaft extending therein is avoided. The pump 30′ illustrated in FIG.5 and the second sheath 20′ surrounding the region 38′ of the shaftcatheter 32′ form a system 200 which makes it possible to test thefunction of the pump 30′ well before an operation and subsequently tocompress the pump by pulling the distal pump unit 31′ into the distalend of the second sheath 20′ and thereby to avoid damage to the shaft.

Although the system according to the first and second aspect can beproduced both with actively decompressible pumps and withself-decompressible pumps, it is suitable in particular forself-decompressible pumps, i.e. pumps, the distal pump unit of whichoutside the sheath automatically assumes the original size again.

In FIG. 6, an intermediate step when pulling the distal pump unit 31′into the lumen L₂ of the second sheath 20′ is represented. It isdetectable that the distal pump 31′ is compressible and can be broughtto a smaller diameter, so that the distal pump unit 31′ can be receivedin the lumen L₂ of the second sheath 20′.

Furthermore, a coupling 39′ which abuts against the shaft catheter 32′is represented in FIG. 6, which coupling enables coupling of the shaftextending in the shaft catheter to a drive unit. Since the coupling 39′has an often larger outer diameter than the inner diameter of the lumenL₂, the second sheath 20′ is generally put on in the distal directionbefore assembly of the coupling 39′ from the proximal end of the shaftcatheter 32′ so that the pump in system 200, i.e. the pump with thesecond sheath 20′ situated proximally to the distal pump unit 31′ andthe premounted coupling 39′, is delivered. In FIG. 6, a slighttrumpet-like widening of the distal end of the second sheath 20′ isrepresented. The trumpet-like widening 24′ facilitates pulling thedistal pump unit 31′ into the lumen L₂ of the second sheath 20′.

In FIG. 7, the distal pump unit 31′ is finally situated completely inthe lumen L₂ of the second sheath 20″. The second sheath 20″ differsfrom the sheath 20′ merely by two premounted gripping units 22″ whichenable better holding or removal of the second sheath 20″ when pullingthe distal pump unit 31′ into the lumen L₂ or subsequent tearing off.Advantageously, in the case of a “pigtail” being present, this islikewise pulled into the lumen L₂ so that the distal pump unit 31′together with components of the pump situated distally to the distalpump unit 31′ is situated in the lumen L₂.

In FIG. 8, it can be detected how the system 200 comprising pump 30′ andsecond sheath 20″ is combined in operating connection with the firstsheath 10 to form a system 100 according to the first aspect of theinvention. Firstly, the second sheath 20″ is introduced by its distalend into the valve of the first sheath 10. As soon as the distal tip ofthe second sheath 20″ abuts against the trumpet-like widening 14 of thefirst sheath 10, by pushing the pump in the distal direction, thepushing being effected by means of pushing the shaft catheter 32′, thepump is transferred from the second sheath 20′ into the first sheath10′. The diameter of the distal pump unit 31′ is hereby reduced furtherto the inner diameter d₁₁ of the lumen L₁.

In FIG. 9, the subsequent step in which the distal pump unit 31′ issituated completely in the lumen L₁ of the first sheath 10 isrepresented. The fact that the distal pump unit 31′ is situatedcompletely in the lumen L₁ of the first sheath 10, can be identifed forexample with reference to a colour marking 50 which is applied on theoutside of the shaft catheter 32′.

Subsequently, the second sheath 20″, which is configured as a“peel-away” sheath, is removed from the shaft catheter 32′ by tearingoff the peel-away sheath from the proximal towards the distal end andpulling it off the shaft catheter 32′. The directed tearing off from theproximal to the distal end can be assisted by notches A but is basedpredominantly on the orientation of the molecular chains of the plasticmaterial which is used from the proximal to the distal direction.

After the peel-away sheath has been removed, the pump 30′ is guidedagain inside the lumen L₁ of the first sheath 10 up to the desiredposition.

Reinforcement of the second sheath 20″ is unnecessary, in particularwhen pulling the distal pump unit 31′ into the distal end of the secondsheath lumen L₂ since the danger of bending of the shaft during apulling movement is greatly reduced.

During transfer of the pump from the second sheath into the firstsheath, as illustrated with reference to FIGS. 7 to 9, the second sheathcan include a structure which reinforces it in the form of an introducedwire, or the tubular portion 21″ of the sheath 20″ is not produced froma flexible plastic material but from a fixed-shape plastic material ormetal.

A further possibility for pulling the pump into the second sheath, whenmoving forwards in the pump 30′ in the distal direction, i.e. inparticular when transferring the pump 30′ from the second sheath intothe first sheath, resides in retaining the second sheath 20″ by means ofa device 40 for retaining the second sheath.

The device for retaining a portion of the second sheath 20″ isrepresented in cross-section in FIG. 11. The device 40 has an upper anda lower half 41 or 42 which are connected to each other via a hinge 43.In the first or second half 41 or 42 there is situated respectively arecess, the recesses in the illustrated, closed state of the device 40defining a cavity 44. The cavity 44 configured as a lumen is configuredfurthermore such that a second sheath 20 can be retained frictionally inthe cavity. This can be achieved either via correspondingly chosen innerdiameters of the cavity 44 or outer diameters of the second sheath 20 orrough surfaces in the region of the cavity 44. Also knobs in the regionof the cavity 44 can produce a frictional fit.

As can be detected with reference to FIG. 10, the cavity 44 extendswithout curvature and hence does not allow any bending of the shaftwhich extends in the shaft catheter 32′ if the latter is pushed forwardsin the distal direction by means of a transverse force. In addition, thedevice 40 makes an improved grip possible for an operator of the system200′ for introducing the pump.

In FIG. 12, the device 40 with the cavity 44 in which a second sheath 20is retained is represented. The distal end of the device 40 thereby lieson the proximal end of the valve 13 of the first sheath 10. In the caseof such a coupling between the first sheath 10 and the second sheath 20,simplified introduction of a pump from the second into the first sheathcan be achieved.

In FIG. 13a , a distal end 22 of an embodiment of the sheath 20,according to the second aspect of the invention is represented. Thedistal end 22 has an internal and external tapering of the edge 23surrounding the lumen L, as a result of which an improved introductionof the sheath into the natural body lumen or a first sheath according tothe first aspect of the invention is possible. Likewise, the distal end22 can be the end of second sheath according to the first aspect of theinvention. A possible proximal end can have the same shape ofconfiguration.

FIG. 13b shows a further variant; an additional feature hereby is thatthe distal end has such a flexible or elastic configuration that itwidens slightly when pulling in the pump head and consequentlyfacilitates insertion. After complete insertion of the pump head, thedistal end again adopts extensively the original shape. Duringintroduction of the distal end of the second sheath into the firstsheath, the distal end of the second sheath can also be fitted by theelastic/flexible tapering to the proximal end of the first sheath andconsequently can facilitate coupling.

The systems, represented in the present documents, according to thefirst, second and third aspect hence enable simplified handling andimproved introduction of pumps into a lumen.

Subsequently, another possible variant of a method for introducing apump into a left ventricle is intended to be portrayed. As a preparatorymeasure, the pump is firstly filled with sterile physiological commonsalt solution and hence completely deaired. Subsequently, the peel-awaysheath placed proximally to the distal pump unit is pushed forwards upto a possibly present discharge hose. The peel-away sheath has adiameter of approx. 10 Fr. After the peel-way sheath has been pushedforwards up to the discharge hose, the peel-away sheath is surrounded bythe device for retaining the second sheath.

Subsequently, the distal pump unit, possibly with a slight rotationalmovement is pulled into the peel-away sheath by exerting a pullingmovement on the shaft catheter in the proximal direction. The pump isdisplaced into the second sheath until a possibly present pigtail islikewise hidden in the peel-away sheath. By means of these steps, it ispossible to test the functional capability of the pump even before anoperational procedure and to introduce the pump only subsequently into asheath without requiring to act under pressure of time. For example, thepuncturing of the vascular system for introducing the first sheath isonly implemented subsequently. In order to save time, it is however alsopossible in this way that an assistant prepares the pump whilst the useralready implements the puncturing in parallel.

After for example a 9 Fr introducer sheath has been introduced into theleft ventricle, a possibly present dilator is pulled out of theintroducer sheath and removed therefrom.

Subsequently, the pump retained in the peel-away sheath, which issurrounded for example by the device for retaining the second sheath,for example a 2 cm long portion of the distal end of the peel-awaysheath protruding at the distal end of the device, is coupled to thehaemostatic valve of the introducer sheath until the tip of thepeel-away sheath abuts inside the introducer sheath. Subsequently, thepump is transferred from the peel-away sheath into the introducer sheathby pushing the shaft catheter.

As soon as the distal pump unit has been transferred completely into theintroducer sheath, as can be checked for example with reference to anoptical marking on the shaft catheter shaft, the device for retainingthe second sheath can be removed from the second sheath and thepeel-away sheath can be torn off and withdrawn from the shaft catheter.Subsequently, the pump is pushed forwards inside the introducer sheathup to the left ventricle. The introducer sheath is subsequently pulledback from the left ventricle up to the beginning of the descendingaorta.

The positioning of the distal pump unit in the left ventricle can bechecked for example by radioscopy. For this purpose, an X-ray-visiblemarking is situated on the pump housing or the pump housing itself isX-ray-visible. Likewise, the outlet region, i.e. the outflow openings ofa discharge hose, should be situated in the region of the ascendingaorta. This can also be checked with an X-ray-visible marking. Apossibly present pigtail catheter tip should abut against the tip of theleft ventricle.

In order to remove the pump from the ventricle, this is pulled back intothe introducer sheath by means of a tensile force applied on the shaftcatheter and is removed, in a compressed state, from the arterialvascular system. Subsequently, the introducer sheath and furtherremaining components are removed from the vascular system.

A further aspect of the invention is the use of a long sheath duringimplantation and explantation of the pump. The long sheath serves notonly, as is common in prior art, for introducing the pump into a naturalbody lumen but for guiding the pump through the sheath lumen to thevicinity of the operating location. It is hereby advantageous if, in themedical field, the sheath has a length between 40 and 120 cm. The lengthis generally determined by the subsequent operating location of the pumpand the physical constitution of the patient. The long sheath can beprovided, on the one hand, by the first sheath of the system accordingto the first aspect of the invention and, on the other hand, by thesheath of a system according to the second aspect of the invention. Aschematic representation of a long sheath and of the distal pump unit inthe operating state can be deduced from FIG. 14.

The long sheath 60, which is formed by a first or second sheath of thesystem according to the first aspect of the invention or a sheath of thesystem according to the second aspect of the invention, ends at theaortic arch 3, the shaft catheter 32 of the pump 30 extending throughthe lumen of the long sheath and emerging at the distal end of thesheath lumen. The distal pump unit 31 is located in the ventricle 4 inthe operating state.

Alternatively, the length of the long sheath can be chosen such thatthis ends in the ventricle before decompression of the pump so that thedistal pump unit is unfolded only in the ventricle.

At the proximal end of the long sheath, the coupling 39′ is situated,which serves for coupling the shaft which extends in the shaft catheterto a drive unit.

The long sheath has such a length that it is possible to place thedistal pump unit in the vicinity of the operating location.

Essentially two functions are attributed to the long sheath. One the onehand, the long sheath enables guidance of the pump to the operatinglocation. Since the pump is compressed in the sheath lumen of the longsheath, conveyance of the pump to the place of use, relative to soleguidance by a guide wire, is simplified. In addition, this serves foravoiding complications or injury to the inner vascular walls. Inparticular in the case self-unfolding pumps, i.e. pumps which have noactive actuatable components for unfolding the distal pump unit, this isa significant simplification relative to guidance of the pump unit bymeans of a guide wire. On the other hand, the long sheath enablessimplified explantation of the pump. The pump unit, after completion ofthe conveying performance, is pulled into the distal end of the longsheath by a pulling movement of the shaft catheter, consequentlycompressed and subsequently withdrawn either through the sheath lumen ofthe long sheath or pulled, together with the long sheath, out of thenatural body lumen.

If the pump is withdrawn together with long sheath out of the naturalbody lumen, bleeding of the femoral artery is stopped with a pressurebandage. Alternatively, the pump can be withdrawn from the sheath lumenof the long sheath. Then a further guide wire can be placed through thelumen of the sheath, via which then, after removal of the sheath, adevice for closing the puncture can be guided. As a result, improvedstoppage of the bleeding can be achieved.

If the first sheath of the system according to the first aspect of theinvention is configured as a long sheath, a system according to thesecond aspect can be introduced into the proximal end of the longsheath. Subsequently, the second sheath is possibly withdrawn from theshaft catheter and the pump is guided through the sheath lumen of thelong sheath to the operating location of the pump.

As an alternative hereto, the long sheath can also be formed by a sheathin the sense of the system of the second aspect of the invention. Afirst sheath, in the sense of the first aspect, can then be dispensedwith. In this variant, the distal pump unit of the pump is firstlypulled into the distal end of the sheath lumen of the sheath accordingto the second aspect of the invention. Subsequently, the sheath in thesense of the second aspect is transferred for example with the help ofthe Seldinger technique into the natural body lumen. The sheath is thenpushed into the vicinity of the operating location of the pump. Thepushing is thereby effected preferably on the outside of the sheath. Inorder to be able to apply this method, the pump is guided via a guidewire. This can be guided for example by a guide wire lumen of thecatheter tip or an additional lumen of the sheath.

Conveyance of the pump to the operating location is possible indifferent ways. After the sheath is situated with its distal end in anatural body lumen, the pump can be guided to the operating location bypushing the shaft catheter out of the sheath and outside the latter. Itmust hereby be ensured that the pump unit must be pushed in the unfoldedstate through the natural body vessel on the basis of the absence ofcompression force of the sheath lumen. In this variant, a long sheath isnot required.

Although a possible alternative for guiding the pump unit to theoperating location is present in the above-described variant, it ispreferred to guide the pump in the folded or compressed state inside thesheath lumen to the vicinity of the operating location. For guidance ofthe sheath inside the vascular system, a rapid-exchange technique can beused, on the one hand, a guide wire being coupled for example to apossibly present catheter tip and the sheath being pushed along theguide wire. Alternatively, the sheath can include a further sheath lumenfor receiving a guide wire, the sheath being pressed forwards towardsthe guide wire.

After the distal pump unit has been pushed out of the distal end of thesheath lumen, the pump is displaced forwards merely by a small distance.The small distance in the case of the human heart as operating locationof the pump is less than 20 cm. In the ratio to the total length of thelong sheath, a small distance is defined by a ratio of the total lengthto the small distance of 3:1 or more.

The sheath can remain for the period of treatment in the natural bodyvascular system—surrounding the shaft catheter. In this case, the pumpcan be pulled into the distal end of the sheath for explantation andsubsequently, as described in one of the preceding paragraphs, beremoved from the natural body vascular system.

Alternatively, if the long sheath concerns a tear-off sheath, this canbe withdrawn and removed after guiding the pump to the operatinglocation. An explantation of the pump is then no longer possible bymeans of the sheath. An additional tool is required which enables theexplantation of the pump and forms an independently patentable subjectof the invention.

The additional tool is only introduced into the vascular system at thetime of the explantation. The additional tool has a lumen forintroducing the distal pump unit. During introduction of the additionaltool, it must be ensured that no non-sterile regions of the shaftcatheter are crossed. By crossing non-sterile regions, germs can beintroduced into the vascular system. In order to achieve a germ-freeintroduction of the additional tool, it is possible to pull a portion ofthe shaft catheter situated in the vascular system out of the lumensince the portion formerly situated in the vessel normally has noforeign germs. The non-sterile region of the shaft catheter which liesoutside the patient during use of the pump and which extends up to thedrive coupling is removed for example by cutting off. The shaft cathetercan also have a suitable predetermined breaking point. In this case, theadditional tool can have a tubular or hose-shaped configuration and canbe guided directly via the severed catheter end. A possible handle wouldfacilitate handling.

The lumen of the additional tool has an inner diameter which correspondsessentially to the outer diameter of the catheter to be explanted or tothe outer diameter of the again compressed pump head. During separationof the non-sterile regions of the shaft catheter, it must hence beensured that only components of the pump which can be inserted into sucha created lumen remain distally to the distal end of the additionaltool.

Alternatively, the additional tool can be configured in the form of alongitudinally divisible tube. In this case, separation of thenon-sterile catheter region would be unnecessary since the tool can alsobe placed directly on the withdrawn region.

In the preceding examples, the system according to the second aspect ofthe invention was described such that, when the system is delivered, thesheath is situated proximally to the distal pump unit and the distalpump unit is pulled by the user of the pump into the distal end of thesheath lumen of the sheath. This has the advantage that the user cantest the functional efficiency of the pump in advance. Alternatively,the system can also be delivered even already with an inserted distalpump unit. The test run of the pump then takes place at the workplace.

If the pump is a self-decompressible pump, the second sheath of thesystem, according to the first aspect of the invention, which servesinter alia for compression of the distal pump unit, can be replaced, ina variant of the system according to the first aspect of the invention,by a crimping tool.

The crimping tool has, at its distal end which is coupled to theproximal end of the first sheath, for example a diaphragm which effectscompression of the distal pump unit of the pump when the distal pumpunit is intended to be transferred into the first sheath. The diaphragmcan be part of a funnel-shaped tapering, the diaphragm being situated atthe distal end of the tapering.

If a crimping tool is used, the distal pump unit is transferred bypushing into the first sheath of the system according to the firstaspect of the invention.

In summary, the systems according to the first, second and third aspectform independent inventions. Further variants of the invention areprovided by a system according to the second aspect with a long sheath,a system according to the first aspect with a long first sheath, asystem according to the first aspect with a long second sheath, a systemaccording to the first aspect with a crimping tool, possibly instead ofa second sheath. The corresponding embodiments of the system accordingto the first, second and third aspect can be applied likewise to thefurther variants of the invention.

The presented treatment methods are likewise included by the invention.This relates in particular to the implantation and/or explantation ofthe pump by means of a long sheath. Also the variants of the inventioncited in the preceding paragraph are suitable for implantation and/orexplantation, as described in the present application.

1-23. (canceled)
 24. A system for introducing a blood pump into a lumenof a body, the system comprising: a first sheath having a first sheathdistal end and a first sheath proximal end, the first sheath forming afirst sheath lumen having a first sheath inner diameter, the firstsheath distal end configured to be positioned in the lumen of the body;a second sheath having a second sheath distal end and a second sheathproximal end, the second sheath forming a second sheath lumen having asecond sheath inner diameter, the second sheath configured to be coupledat the second sheath distal end to the first sheath proximal end; and ahousing, the housing comprising a cavity sized to retain at least aportion of the second sheath, the cavity having a degree of curvature.25. The system of claim 24, wherein the cavity is configured to have adegree of curvature of less than 10 degrees.
 26. The system of claim 24,wherein the cavity is configured to have a degree of curvature of lessthan 1 degree.
 27. The system of claim 24, wherein the housing isconfigured to prevent bending of the at least a portion of the secondsheath further than the degree of curvature of the cavity.
 28. Thesystem of claim 24, wherein the at least a portion of the second sheathretained by the cavity is equal to half of a length of the secondsheath.
 29. The system of claim 24, wherein the cavity is configured tofrictionally retain the at least a portion of the second sheath.
 30. Thesystem of claim 29, wherein an inner diameter of the cavity is less thanan outer diameter of the second sheath.
 31. The system of claim 29,wherein the cavity has a roughened surface.
 32. The system of claim 24,the housing further comprising an upper portion and a lower portion,wherein the cavity is formed between the upper portion and the lowerportion.
 33. The system of claim 32, wherein the cavity is formed as arecess in the upper portion.
 34. The system of claim 32, wherein thecavity is formed as a recess in the lower portion.
 35. The system ofclaim 32, wherein the upper portion and the lower portion are coupled bya hinge.
 36. The system of claim 35, wherein the housing is configuredto clamp the at least a portion of the second sheath.
 37. The system ofclaim 24, the system further comprising a first sheath valve coupled tothe first sheath proximal end.
 38. The system of claim 37, wherein adistal end of the housing is positioned proximate a proximal end of thefirst sheath valve.
 39. A method of introducing a blood pump having acatheter into a lumen of a body, the method comprising: inserting adistal end portion of a first sheath into the lumen of the body;retaining at least a portion of a second sheath in a cavity of ahousing, the cavity having a degree of curvature; pulling the blood pumpby the catheter into a distal end of the second sheath, such that anentire length of the blood pump is within the second sheath; couplingthe distal end of the second sheath to a proximal end of the firstsheath; transferring the blood pump from the second sheath into thefirst sheath; and inserting the blood pump into the lumen of the bodythrough the first sheath.
 40. The method of claim 39, whereintransferring the blood pump from the second sheath into the first sheathcomprises pushing the catheter of the blood pump to move the blood pumpout of the second sheath and into the first sheath.
 41. The method ofclaim 40, wherein pulling the blood pump by the catheter into a distalend of the second sheath further comprises pulling the blood pump intothe portion of the second sheath retained in the cavity of the housing.42. The method of claim 41, further comprising removing the secondsheath and the housing from the first sheath.
 43. The method of claim42, wherein pushing the catheter of the blood pump to move the bloodpump out of the second sheath and into the first sheath comprises movingthe blood pump through a valve coupled to the proximal end of the firstsheath